In the 3rd Generation Partnership Project (3GPP), a radio access method and a radio network for cellular mobile communications (hereinafter referred to as “Long Term Evolution (LTE)”, or “Evolved Universal Terrestrial Radio Access (EUTRA)”) have been studied. In LTE, a base station device is also referred to as an evolved NodeB (eNodeB), and a terminal device is also referred to as user equipment (UE). LTE is a cellular communication system in which an area is divided into multiple cells to form a cellular pattern, each of the cells being served by a base station device. A single base station device may manage multiple cells.
LTE supports a time division duplex (TDD). LTE that employs a TDD scheme is also referred to as TD-LTE or LTE TDD. Uplink signals and downlink signals are time division multiplexed in TDD. LTE also supports a frequency division duplex (FDD).
In 3GPP, career aggregation has been specified which allows a terminal device to perform simultaneous transmission and/or reception in up to five serving cells (component careers).
In 3GPP, a configuration where a terminal device performs simultaneous transmission and/or reception in more than five serving cells (component careers) has been considered (NPL 1). Furthermore, a configuration where a terminal device transmits a physical uplink control channel in a secondary cell which is a serving cell other than a primary cell has been considered (NPL 1).